Patent application describes a system in which a password secret is stored in memory on a special power adapter that is associated with a specific device. Users who forgot the password necessary to access their device would first have to connect the adapter before they were able to view the recovery secret. The development would, in essence, turn power cords and other peripherals into a second factor that would make it harder for thieves to gain access to devices they steal. The invention is designed to address problems with current password recovery mechanisms and authentication mechanisms.
Source: https://threatpost.com/apple-patent-links-power-cord-password-recovery-010612/76070/